as a stove, radio, refrigerator. Balan (15) has assembled comparable data on Buenos Aires, Santiago, Mexico City, Monterrey, San Salvador, and Guatemala City. He finds that the socioeconomic gap between natives and migrants in some of these cities is large while in others it is small or nonexistent. Although migrants in nearly all of these cities have lower educational attainments, their occupational distribution, based on a one-digit code, shows they do at least as well as natives in such cities as Santiago, San Salvador, and Guatemala City. In his interpretation of these differences Balan found it useful to consider the position of migrants in terms of the proportion originating in rural areas, their "credentials" (formal requirements such as educational degrees), and the rate of creation of higher status jobs in the community of destination.
The Monterrey data demonstrate that migrant-native differentials are not at all a simple matter. In Table 8 occupation and income data are given for the six Migratory Status Groups, as identified earlier. When the two extreme groups are compared, Short Exposure Migrants and Second Generation Natives, the latter do considerably better even when we control for age. However, there is no steady progression among the six groups, for the Long Exposure Migrants do as well as either the Natives by Adoption or First Generation Natives, and this again holds after controlling for age. The explanation for the superior performance of Long Exposure Migrants is apparently not simply due to their longer exposure in the city, but also to their greater selectivity (17).
The argument advanced here does not deny that in aggregate terms migrants rank below natives on socioeconomic indicators. Doubtless in the great majority of large cities in developing societies they do. But the important point to remember is that overall they do not rank far below the natives, or at least as low as would reasonably be expected, considering the important rural component of much of the in-migration to these cities. Whatever the socio-economic ranking of migrants and natives, the point to be stressed is that both groups are lower than is desirable.
There is also the question of migrant-native differences in social mobility or, more precisely, occupational mobility, for that is the way social mobility almost invariably is measured. The argument of Blau and Duncan (43, p. 274), although it derives from their research in the United States, is relevant. They maintain that migration promotes social mobility.
As a mechanism of selection and redistribution of manpower, migration furthers occupational mobility. Indeed, it is essential for occupational mobility on a wide scale in a highly diversified society because it alone can alter the opportunity structure in which a given man completes.
In terms of the communitv of destination, in this case laree cities. Blauit should be kept in mind that none of the above groups had less than half of their populations in neighborhood networks. The highest are those from farm backgrounds. They are the group who must make the (rreatest adjustment in stvlp. of livino nnH tVip.rpfnrp nrp nrp«nmali1\/ m^et inhe predominantly male rural-urban migration, in the multilingual character of the society, in the existence of polygamy, and